Other Uveal Tumors
Hemangiomas of the choroid occur in 2 specific forms: circumscribed (ie, localized) and diffuse. Circumscribed choroidal hemangioma typically occurs in patients without systemic disorders. Diffuse choroidal hemangioma is generally seen in patients with Sturge-Weber syndrome (encephalofacial angiomatosis).
Figure 12-28 Choroidal hemangioma with a large number of thin-walled, variably sized vessels within the choroid. A, Low-magnification view shows exudative retinal detachment overlying the lesion (asterisk). Arrows designate Bruch membrane. B, Higher-magnification photomicrograph from a different patient showing the numerous choroidal blood vessels; arrows designate Bruch membrane.
(Part A courtesy of Nasreen A. Syed, MD; part B courtesy of Steffen Heegaard, MD.)
Histologically, both forms show collections of variably sized vessels within the choroid (Fig 12-28). The lesions may appear as predominantly capillary hemangiomas, cavernous hemangiomas, or a mix of the two. There may be compressed melanocytes, hyperplastic RPE, and fibrous tissue proliferation in the adjacent and overlying choroid. See Chapter 18 (particularly Figs 18-1, 18-2) in this volume for detailed discussion of choroidal hemangiomas. See also BCSC Section 12, Retina and Vitreous.
Choroidal osteomas are benign bony tumors that typically arise from the juxtapapillary choroid. They are seen in adolescent and young adult patients and are more common in females. The characteristic lesion appears yellow to orange and has well-defined margins (see Chapter 17, Fig 17-12D). These tumors may affect vision in the involved eye and may lead to development of choroidal neovascularization. The tumor is located in the peripapillary choroid and, histologically, is composed of compact bone (Fig 12-29). The intratrabecular spaces are filled with loose connective tissue that contains large and small blood vessels, vacuolated mesenchymal cells, and scattered mast cells. The bony trabeculae contain osteocytes, cement lines, and occasional osteoclasts.
Figure 12-29 Choroidal osteoma. This choristomatous lesion is composed of compact bone (asterisk) and intratrabecular connective tissue.
(Courtesy of Steffen Heegaard, MD.)
Figure 12-30 Choroidal lymphoma. A, Diffuse infiltration of the choroid by lymphoma (blue cells). R = RPE; S = sclera. B, Higher magnification demonstrates atypical pleomorphic lymphocytes.
(Courtesy of Hans E. Grossniklaus, MD.)
The choroid may be the site of lymphoid proliferation, either as a primary ocular process or in association with systemic lymphoproliferative disease.
Primary choroidal lymphomas (previously known as uveal lymphoid hyperplasia or uveal lymphoid infiltration) are mostly low-grade, B-cell tumors similar to extranodal marginal zone B-cell lymphomas occurring elsewhere in the body. High-grade choroidal lymphomas (Fig 12-30) are usually secondary to systemic disease or are an extension of vitreoretinal lymphoma. The classification of lymphoproliferative lesions is further discussed in Chapter 14.
Sagoo MS, Mehta H, Swampillai AJ, et al. Primary intraocular lymphoma. Surv Ophthalmol. 2014;59(5):503–516.
Figure 12-31 Choroidal neurofibromatosis. The choroid is diffusely infiltrated by spindle-shaped cells with slender, wavy nuclei; occasional neurons (arrowhead); and enlarged choroidal nerves (asterisks). R = RPE.
(Courtesy of Michele Bloomer, MD.)
Neural sheath tumors
Neurilemomas (schwannomas) and neurofibromas are rare in the uveal tract. Multiple neurofibromas may occur in the ciliary body, iris, and choroid in patients with neurofibromatosis 1 (Fig 12-31). For more information on these tumors, see Chapter 14.
Neoplasms arising from the smooth muscle of the ciliary body have been reported in rare instances. They typically occur in young adult females. When leiomyoma occurs, it may be confused clinically with amelanotic melanoma or neurofibroma. Histologically, leiomyoma is identical to leiomyoma of the uterus (uterine fibroid) and consists of a proliferation of tightly packed, slender spindle cells lacking pigment. Immunohistochemical stains may be useful in diagnosing leiomyomas because these tumors express smooth muscle–related antigens. They also may express hormonal receptors such as progesterone and androgen receptor. Under light microscopy and transmission electron microscopy, leiomyoma sometimes exhibits both myogenic and neurogenic differentiation. In such cases, the tumor is called mesectodermal leiomyoma.
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.